Cooling apparatus



Jan. 30, 1940. J. w. McNULTY 2,188,370

' COOLING APPARATUS Filed Sept. 17, 1936 INVENTOR JOHN \MMgNuu'Y.

BY u 1.61%

ATTORNEY Patented Jan. 30, 1940 UNITED STATES PATIENT OFFICE COOLING APPARATUS Pennsylvania Application September 17, 1936, Serial No. 101,252

7 Claims.

I object to provide improved means of this character.

A further object is to provide simple and compact apparatus.

Another object is to provide an improved arrangement for partial load operation.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, and forming a part of this application, in which:

The single figure is a diagrammatic view of refrigerating apparatus constructed in accordance with my invention, the evaporator being shown in vertical section.

Referring now to the drawing in detail, I show an evaporator or cold tank I0 having a partition II dividing the same into an upper chamber I2 and a lower chamber I3. The present apparatus is designed for cooling the liquid in stages, the 25 liquid first passing through and being partially cooled in the upper chamber I2 and then passing through and being further cooled in the lower chamber I3.

Each chamber is provided with suitable means for causing the liquid to rain or fall therethrough in finely-divided particles. In the present embodiment, such means comprises a cup-shaped receptacle I4 having an annular weir I5 over which the liquid flows. Bafiies I6 may be pro- 35 vided below the weir IS in the path of the falling liquid, so as to break up the liquid into smaller particles and subject the same more thoroughly to the low pressure maintained in the chamber.

The liquid to be cooled is delivered through a supply conduit H to the receptacle I4 of the upper chamber I2. The liquid collecting in the bottom of the chamber I2 is conveyed to the lower chamber I3 through conduit means I8 disposed within the lower chamber I3 and arranged to form a loop 45 seal between said chambers. The conduit means or loop seal I8 comprises an inner conduit I9 providing a passage and an outer telescoping conduit 2| providing a passage22. The passages 20 and 22 communicate at their upper ends with the 50 chambers I2 and I3, respectively, and with each other at their lower ends, the lower end of the conduit 2I heing'closed and spaced from the lower open end of the inner conduit I9. Adischarge or tail pipe 23 is connected to the bottom of the lower chamber I3 for removing theliquid collecting therein. The liquid is then conveyed in any suitable manner, as by conduit means and a pump (not shown), to the point of use and returned to the refrigerating apparatus through the supply conduit II.

A by-pass conduit 24 is connected to the passage 22, intermediate the upper and lower ends thereof, and to the supply conduitII. It is provided with a valve 25 adapted to control the flow of liquid therethrough. The by-pass conduit 24 and the portion of the supply conduit I'I connected thereto are disposed below the receptacle I4 of the upper chamber I2, so that, when the valve 25 is open the liquid supplied through the conduit I'I flows through the conduit 24 to the receptacle H in the lower chamber I3 and by-passes the upper chamber I2. The supply conduit "is provided with a valve 26 actuated by a float 21 in response to the level of the liquid in the bottom of the chamber I3. As the level tends to drop the valve is opened and vice versa, thereby controlling flow of liquid so as to maintain said level substantially constant. 7

There may also be provided a by-pass conduit 24a connected at one end to the supply conduit [1, preferably below the by-pass conduit 24, and at its other end to the tail pipe 23. The by-pass conduit 24a isprovided with a valve 250., and when said valve is open, the water may flow through said conduit, by-passing both chambers I2 and I3.

The chambers I2 and I3 are provided with suitable fluid translating elements, such as ejectors 30 and 3|, respectively, for withdrawing vapor therefrom and for maintaining reduced pressure conditions therein. Each chamber has a vapor outlet nozzle 32 connectedthrou'gh a conduit 33 to the suction inlet 34 of the associated ejector.

Motive fluid, usually steam under suitable pressure, for motivating the ejectors is delivered through a s pply conduit 35 and branch conduits 36 and3'l. The latter are provided with valves 38 and 39 for controlling the supply of motive fluid individually to the respective chambers. The valves 38 and 38 are adapted to be opened by solenoids and 42, respectively, and the latter are controlled by switches" and 44, respectively, of a thermostatic control 45. The latter also includes a thermostatic bulb 4G responsive to the temperature of the cooled water passing through the tail pipe 23 and connected to a bellows 48. The latter is adapted to close the switches 44and 43 in response to successively higher predeter- .mined temperatures, respectively, and to open said switches in the reverse order upon decrease below said temperatures.

The present invention contemplates a novel means for actuating the valve 25, which is to be closed when the ejector 30 is operating and to be opened when the ejector 30 is shut down. The

.valve 25 is connected to a diaphragm 52. "The pressure of the motive fluid supplied to the ejector, that is, the motive fluid in the conduit 36 beyond the valve 38 is conveyed through a conduit 53 to the diaphragm 52 and imposed thereon in valve closing direction. The valve is biased in open direction by a spring 54. When the valve 38 is opened to admit motive fluid to the ejector 30, the pressure applied to the diaphragm 52 is suflicient to completely close the valve 25, and, when the valve 38 is closed to shut off the supply of motive fluid to the ejector 30, the spring 54 fully opens the valve 25.

The valve 25a is adapted to be fully closed in a similarmanner by a diaphragm 52a when subjected to steam pressure supplied to the ejector 3|, which pressure is communicated through a conduit 53:: as shown. It is adapted to be fully opened by a spring 54a in the absence of pressure on the diaphragm 52a.

The ejectors 30 and 3| discharge into a surface condenser 55 havingan air and condensate outlet 55, a cooling water inlet 51 and a cooling water outlet 58. The condenser 55 is'of the type known as a simple condenser, that is, the ejectors 30 and 3| discharge into a common condensing space therein. It is to be understood, however, that any suitable form of condensing apparatus, may be provided; it may be either a surface condenser 01: a barometric condenser, and it may be either a simple condenser or a stage condenser having separate compartments connected to the several ejectors.

Operation Assume first a' refrigerating demand sufficiently great to require the operation of both ejectors. Such demand is reflected by a temperature in the tailpipe 23 sufiiciently high to cause thethermostat 45 to close both switches,

' thereby energizing solenoids 4| and 42 and opening the valves 38 and 39. Motive steam is supplied to both ejectors to eifect operation there of. Opening of the valves 38 and 39 causes steam pressure to be communicated through the conduits 53 and 53a to the diaphragms 52 and 52a, on which it acts to close the valves 25 and chamber I2 then flows downwardly through the passage 20, upwardly through the passage 22, over the upper edge of the weir I5, and fails I through the lower chamber I3. The ejector 3| removes vapor from the lower chamber I3 'and maintains a reduced pressure therein sufliciently low to efiect partial vaporization and further temperature reduction of the water falling through the chamber. The water is then removed through the tailpipe 23. I

It niay be noted' thatethe location of the outlet 32 at the bottom of the evaporator chamber in each case efiects progressive cooling of the water to some extent in a manner analogous to counterflow action in heat transfer apparatus. The absolute vapor pressure decreases slightly from the top to the bottom of the chamber, since some pressure drop is necessary to effect flow of the vapor to the outlet. moving downwardly is subjected to progressively lower pressure and is thus progressively cooled to the temperature corresponding 'to the lowest pressure adjacent the outlet 32. The major portion of the cooling, however, is efiected by partial evaporation of the water as it spills over the weir I5.

In the above described operation, the pressure maintained within the chamber I3 is at a lower value than that maintained in the chamber I2, for the reason that the water is at a lower ternperature in the chamber I3. This difference in pressure in the two chambers is taken'care of by the loop seal I8.

Thus, the water Assume now that the refrigerating demand decreases to a sumcient extent to require the operation of only one ejector. This is reflected by a decrease in the temperature of the water in the tailpipe 23 to a value between the above mentioned predetermined temperatures at which the switches 44 and 43 are opened and' closed.

According y, the thermostat 45 opens the switch 43, deenrgizing the solenoid 4| and closing the valve 38. The supply of steam tothe ejector is shut oil so that operation of said ejector is terminated. Condenser pressure is communicated through'the ejector 30 to thechamber I2 and as the'temperature of vapor at condenser pressure is above the temperature of the water supplied through the conduit I1, heating of .water would result if it continued to flow through the chamber IL The closing of the valve 38 removes steam pressure from the diaphragm 52, so that the spring 54 opens the valve 25. Water from the supply conduit I! now flows through the valve 25 and the by-pass conduit 24 directly to the passage 22, thereby bypassing the upper chamber I2; such flow being effected by reason of the fact that the conduit 25 and the portion of the conduit I! communicating therewith are below the level of the receptacle I4 in the chamber I2. The higher pressure in the chamber I2 causes the water in the conduit I! to drop to a level approximately that indicated at 59, which is above the connection with the conduit 24 but sufliciently below the upper edge of the weir I5 in the chamber I3 to provide a difference in head for balancing the difference in pressures. The higher pressure in the chamber I2 also causes the water in the passage 20 to drop to a level,

I such as indicated at 6|, such that the difference in head between this level and the upper edge of the weir I5 in the chamber I3 balances the difference in pressures. The level 59 is above the level 6|, due to the fact that the pressure of the water in the conduit I1 is higher than that in the loop sealJB, a pressure diflerence being required toforce the water through the valve 25 and the conduit 24.

Partial load operation of apparatus now takes place as follows: Water delivered through the conduit I'I passes through the valve 25, the bypass conduit 24 and the passage 22 to the upper edge of the weir I5 in the chamber I3. ,As it falls through the chamber I3, it is partially vaporized and cooled by reason of theaction 01 the ejector 3| in the same manner as described above. It is then removed through the tailpipe 23. The chamber l2 does not contain water at such time, the water therein having been drained into the passage 20. The water levels indicated at 59 and BI are subjected to the higher temperature of condenser pressure, but inasmuch as this Water is in relatively static condition, the amount of heat added to the water is negligible.

Upon further decrease in refrigerating demand, the temperature of the cooled water decreases sufliciently to cause the thermostat 45 to open the switch 45 and terminate operation of the ejector 3|, by closing the steam valve 39.

Flow of water through the chamber l3 may result in heating thereof, by reason of condenser vapor pressure communicated through the inactive ejector 3l. In such case, the water may be by-passed through the conduit 24a, the valve 25a being opened by the spring 54a when the valve 39 cuts off steam pressure from the dia phragm 52a.

Upon subsequent increase in refrigerating load, the temperature again rises until the thermostat 45 closes the switch 44 to effect partial load operation as described above, and upon further increase, the switch 43 is also closed to effect full load operation.

While I have shown my invention as embodied in apparatus having two evaporator chambers, it is to be understoodthat it is equally applicable to apparatus having a greater number of evaporator chambers.

While I have shown my invention in but one .form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In refrigerating apparatus, the combination of first and second evaporator chambers, first and second ejectors connected to said first and second chambers, respectively, for withdrawing vapor therefrom, means for supplying motive fluid and for controlling the admission thereof individually to said ejectors, means for delivering liquid to be cooled to said first chamber,

means for conveying liquid from said first chamber to said second chamber, means for withdrawing liquid from said second chamber, bypass conduit means for conveying liquid from said delivery means to the second chamber for by-passing the first chamber, a valve in said by-pass conduit, and means for closing said valve in response to pressure of the motive fluid admitted to the first ejector and for opening the valve in the absence of said pressure, whereby when the first ejector is shut down, the liquid to be cooled by-passes the first chamber.

2. In refrigerating apparatus, the combination of first and second evaporator chambers, first and second ejectors connected to said first and second chambers, respectively, for withdrawing vapor therefrom, means for supplying motive fluid to said ejectors, first and second valves for controlling the admission of motive fluid to said first and second ejectors, respectively, means for delivering liquid to be cooled to said first chamber, means for conveying liquid from said first chamber to said second chamber, means for withdrawing liquid from said second chamber, by-pass conduit means for conveying liquid from said delivering means to the second chamber for by-passing the first chamber, a valve in said by-pass conduit, a pressure responsive element for closing the valve in said by-pass conduit, and means directly responsive to opening of said first valve for supplying fiuid pressure to said pressure responsive element, whereby when the first ejector is shut down, the liquid to be cooled by-passes the first chamber.

3. In refrigerating apparatus, the combination of first and second evaporator chambers, the first chamber being disposed at a higher level than the second chamber, a fluid translating element connected to each chamber for withdrawing vapor therefrom and maintaining a reduced pressure therein, conduit means for conveying liquid to be cooled to said first chamber, means for conveying liquid from the first chamber to the second chamber, means for withdrawing liquid from the second chamber, by-pass conduit means for conveying liquid from said first-mentioned conduit means to the second chamber, and a valve in said by-pass conduit means, the point of communication between said by-pass conduit means and said first-mentioned conduit means being disposed at a level substantially below the level at which liquid to be cooled is delivered from said first-mentioned conduit means into the reduced pressure region in said first chamber, whereby liquid flows through the by-pass conduit means into the second chamber and by-passes the first chamber when the valve in said by-pass conduit means is open.

4. In refrigerating apparatus, the combination of first and second evaporator chambers, the first chamber being disposed immediately above the second chamber, an ejector connected to each chamber for withdrawing vapor therefrom, means for supplying motive fiuid and for controlling the admission thereof individually to said ejectors, conduit means for conveying liquid to be cooled to said first chamber, means for conveying liquid from the first chamber to the second chamber, means for withdrawing liquid from the second chamber, by-pass conduit means for conveying liquid from said first-mentioned conduit means to the second chamber, a valve in said by-pass conduit means, the several conduit means being so arranged that the liquid fiows through the by-pass conduit means into the second chamber and by-passes the first chamber when the valve in said by-pass conduit means is open, and means responsive to the pressure of the motive fiuid admitted to the ejector of said first chamber for closing said valve.

5. In refrigerating apparatus, the combination of first and second evaporator chambers, the first chamber being disposed immediately above the second chamber, a fluid translating element connected to each chamber for withdrawing vapor therefrom, means for supplying liquid to be cooled to said first chamber, conduit means for conveying liquid from said first chamber to said second chamber and formed to provide a loop seal therebetween, said conduit means comprising a vertical inner conduit communicating at its upper end with said first chamber for flow of liquid downwardly therethrough and an outer conduit closed at its lower end, telescoping the inner conduit and forming therewith a passage communicating at its lower end with the inner conduit and at its upper end with said second chamber for flow of liquid upwardn there through, and means for withdrawing liquid from said second chamber.

6. In refrigerating apparatus, the combination Y of first and second evaporator chambers, the first ifiyer end, telescoping the inner conduit and forming therewith a passage communicating at its lower end with the inner conduit and at its upper end with said second chamber for flow of liquid upwardly therethrough, and means for withdrawing liquid from said second chamber.

7. In refrigerating apparatus, the combination of evaporator means, a plurality of fluid translating elements connected to said evaporator means for withdrawing vapor therefrom, conduit means for convey liquid to be cooled to said evaporator means, means for withdrawin liquid from said evaporator means, a connection between said conduit means and said withdrawal means by-passing the entire evaporator means, a valve in said connection, means for rendering said fluid translating. elements individually active or inactive, means controlled by the lastmentioned means for opening said valve to bypass liquid from said conduit means to said liquid withdrawal means in response to the action of the last-mentioned means rendering all of said fluid translating elements inactive and for fully closing said valve in response to the action of thelast-mentioned means rendering a fluid translating element active.

JOHN W. MONULTY. 

